1. Field of the Invention
The present invention pertains to a device for mounting an original onto an image reading drum in an image scanning system.
2. Description of the Prior Art
Drum-type image scanning systems generally comprise a transparent image reading drum, on which an original to be scanned is mounted.
The original is manually attached and fixed onto the cylindrical surface of the image reading drum with adhesive tape, and is detached from the drum by peeling the adhesive tape off the original. This manual attachment, however, does not assure complete contact of the original with the image reading drum, and in many cases, its poor contact with or partial separation from the drum causes Newton's rings.
When the original is large in size, an operator can find Newton's rings without any difficulty and adjust the attachment of the original to the image reading drum. On the other hand, it is rather difficult to find Newton's rings on a small-sized original, and the obtained image signals sometimes include signals caused by Newton's rings. In other words, conventional manual attachment does not efficiently prevent occurrence of Newton's rings especially for a small-sized original.
There are some known techniques used for prevention of Newton's rings. One proposed technique is to spray powdery stone (particularly talc) on the lower surface of the original before mounting the original on the image reading drum, and another proposed technique is to use an image reading drum with a window. The former technique requires skill for evenly spraying the powdery stone, as well as considerable time and labor. The latter technique limits the position of the original to the window on the image reading drum, thus wasting the residual space on the drum.